MK Indy Engine Install

Having rebuilt my engine, it was time to mate the engine with the gearbox and complete the MK Indy engine install into the chassis.

Now, the day I ended up putting the engine in the car, I didn’t plan to put it in the car. I aimed to get the rear oil seal changed, the new clutch in and the gearbox on so it was ready for installation. For once I ended up overachieving!

Engine Stand

The first thing was to lift the engine off the engine stand and remount the engine from the side to get access to the main bearing seal. This was the current access to the main bearing seal:

So we moved the engine stand to the drive and lifted the engine with the engine hoist. This was where we found the first problem. The bolts used to mount the engine on the stand from the bell housing (as I had it) were not the same as the bolts needed to mount the engine to the stand on the side of the engine. I didn’t have the correct bolts long enough to do this, which were M10 fine thread.

Rear Oil Seal

So we decided to leave the engine hanging from the hoist and change the rear oil seal from there. To do this I had 3D printed a MX-5 Rear Main Crank Seal Install Tool to help press the new seal into the correct depth. I managed to removed the old seal by screwing a small screw into the seal and pulling, combined with a small screwdriver Down the side of the seal. The 3D printed install tool made the fitment of the new seal nice and easy with a rubber mallet.

Fly Wheel

Next was to fit the new spigot bearing to the cleaned up fly wheel. This was done by pressing the new bearing in with a bolt, 2x large flat washers and the old bearing. The fly wheel was then bolted on using the original bolts with a bit of Locktite 243.

Clutch Install

We installed the clutch next. This was the standard Exedy MX-5 clutch which gets good reviews at handling up to 250bhp and gives a nice standard smooth driving bite. I bought a clutch alignment tool to make this a lot easier, which worked very well.

We then noticed a mistake! We had not installed the aluminium gasket between the engine and gearbox before putting on the flywheel. For some reason I had it in my head it could be added after. So we had to redo this all again and take off the clutch and flywheel. Luckily this didn’t take long.

Gearbox Preperation

Now the engine was ready we then set about putting the finishing touches to the gearbox.

The gearbox had already been cleaned and painted so the main things to do was modify the clutch, fork and replace seals and bearings.

Clutch Fork

The manual shows you how to modify the clutch fork by taking a notch out of the very end. This is so that when the clutch is fully depressed the fork does not hit the chassis or brake pipes. This was easy to do with a dremel and hand file. I then painted it to protect the exposed steel with the Simonez Satin Black paint. The clutch fork rubber boot was cleaned with some Autoglym Rubber Restorer which made it look like new. I then reinstalled the clutch fork with a new thrust bearing.

Output Shaft Seal

I then decided to shave a small amount off the underside of the gearbox, right under the output shaft seal. This is to provide more clearance for the nut that secures the new gearbox bracket to the chassis. This was after seeing it as a recommendation by guys on the forum. It is much easier to do this now than once the gearbox is in the car. I used a dremel to shave off about 5mm of material.

I also replaced the output shaft seal for good measure. This was a simple lever the old one out with a flat head screwdriver and then gently knock the new one in with a block of wood and a rubber mallet and a bit of oil as lubricant.

Remove Gear Lever

The final thing to prepare the gearbox was to remove the gear lever. Doing this provides better clearance when install the engine and gearbox later. This was simply removal of the 4x bolts. I needed to remove this anyway as I have new bushes for the gear lever to go in. I then just taped up the hole with masking tape to keep it clean

Connecting Gearbox to Engine

So now it was time to connect the gearbox back to the engine. I made sure that the gearbox spline input shaft was cleaned with a wire brush and added grease to help it go into the clutch. We had already tried fitting the clutch (before fitting it to the engine) to make sure it fitted OK, which it did.

Then we used the makeshift wooden gearbox support that I made when the engine/ gearbox came out of the car to place the gearbox on. Then we lowered the engine down still hanging on the engine hoist.

After a lot of wriggling, banging with a rubber mallet and fair dose of swearing, coupled with some well timed support from a neighbour, we finally got the gearbox mated to the engine.

Fitting the Engine

Now this was the point I had planned to get to on the day. The power pack (engine/ gearbox) joined back together and ready to do the MK Indy engine install. I had the intention of lifting the power pack onto the wodden stand at the side of the garage and leaving it there for another day. My mate Dave was round and just said “I know this might be a stupid question, but why don’t we just put it straight into the car?”. I paused for a minute, thought some more and realised this wasn’t such a stupid idea. It was probably actually easier to put it in the car than at the side of the car. So that was it decision made, let’s put it in the car!

We lifted the power pack and adjusted the chains so it was tilted at an angle with the gearbox pointing down a bit. Then raised it up quite high with the engine hoist on max reach. Then slowly pushed the engine hoist towards the car.

We placed towels over the front of the chassis and over the top of the gearbox to protect both during install. I removed both engine mounts initially to give more clearance to get the engine in. Then added them back in once the engine was sitting almost in position.

With my mate Dave controlling the hoist and my Son and I guiding the engine in, we gradually got there and the engine went in surprisingly easily in the end!

The clearance to the new gearbox mount was just perfect with the bit I had shaved off earlier. Without this it would have clashed.

Sorting Clearance Issues

Once the engine was in there were a few clearance issues I wasn’t completely happy about which were quite easy to rectify.

Issue 1: Gear Lever and Fuel Pipe

The corner of the gear lever turret was very close to my routing of the fuel pipe, within a few mm. Whilst this bit would not be moving that much I wanted a bit more clearance.

I simply carefully bent the fuel pipe further away from the gearbox. It wouldn’t have been an issue if I mounted the brake pipe about 20mm higher at this point. Easy to fix though, the images below show the bracket that I rebent outwards to move the fuel line further away from the gearbox.

Issue 2: Propshaft and Brake Pipe

On the rear right of the transmission tunnel, the rear brake pipe came very close to the Propshaft. This was because I had routed it in the inside of the transmission tunnel. This was again down to my choice of routing at the start. I had about 5mm of clearance.

This didn’t feel enough so I decided to move the brake pipe to the underside of the chassis rail. Fortunately I could do this without removing the pipe. I just cut the existing clips and adding 2x more pipe clips on the underside of the round chassis rail and gently bending the brake pipe. The position before (top) and after the move (bottom) are shown below.

Issue 3: Gearbox and Chassis

On the passenger side of the transmission tunnel, near the front the gearbox was touching the round chassis rail. By releasing the engine mounts I managed to move the engine over by about 5mm which gave just about enough clearance. Hopefully this won’t move too much. Something to keep and eye on. Worst case I might need to shave a bit of the gearbox casing. For the moment I’m happy.

Summary of Build Costs and Hours

Here is a summary of the costs and person hours (total number of hours for every person that has helped) for the build so far. This should hopefully help others with the planning of their builds, by providing cost and time actually incurred for this build. A more detailed breakdown of all the costs and hours worked on the build to date can be viewed here.

Person Hours Worked This Post
Fit Clutch1 hrs
Join Engine and Transmission1 hrs
Fit Engine and Gearbox in Car1 hrs
Car Build Costs This Post
Exedy Clutch Kit Standard Three Piece, 1.8 Mazda MX5 Mk1/2/2.5£134
MX5 Clutch Spigot Pilot Flywheel Bearing£7
Clutch Alignment Tool£11
Totals This Post To Date All Posts
Person Hours Worked 3 hrs 400 hrs 404 hrs
Car Build £152 £13,192 £13,202
Tools / Consumables £0 £459 £470
Total Cost £152 £13,651 £13,672

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